Embolic materials

Abstract

The object of the present invention is to provide an embolizing material which is easily handleable and stable in quality and is solved by providing an embolizing material comprising an ester derivative of a polysaccharide having a weight-average molecular weight of 10,000-500,000 daltons and an average substitution degree of acyl group of over two; an embolizing agent for arteriovenous aneurysm, which comprises the embolizing material and an appropriate physiologically acceptable water-soluble organic acid; and a method of producing an embolizing agent, which comprises a step of dissolving the embolizing material in an appropriate physiologically acceptable water-soluble organic solvent.

1. In a method for embolizing an arteriovenous aneurysm in a patient, the improvement comprising administering to said patient an ester derivative of a polysaccharide, wherein the polysaccharide is selected from the group consisting of pullulan and elsinan as an embolizing material, said ester derivative (i) having a weight-average molecular weight of 10,000 to 500,000 daltons, (ii) having a ratio of the weight-average molecular weight to the number average molecular weight of below two, (iii) having an average substitution degree of acyl group of greater than 2.5 (iv) being preparable into a solution with a viscosity of below 1,000 centipoises (cps) at 20° C. when dissolved in dimethyl sulfoxide; (v) being substantially insoluble in blood, and (vi) having a solubility in dimethyl sulfoxide of at least 10 mg/ml at 20° C. 
     
     
       2. An embolizing agent for arteriovenous aneurysm, comprising an embolizing material comprising (A) an ester derivative of a polysaccharide, wherein said polysaccharide is selected from the group consisting of pullulan and elsinan, (I) having a weight-average molecular weight of 10,000 to 500,000 daltons, (ii) having a ratio of the weight-average molecular weight to the number average molecular weight of below two, (iii) having an average substitution degree of acyl group of greater than 2.5, (iv) being preparable into a solution with a viscosity of below 1,000 centipoises (cps) at 20° C. when dissolved in dimthyl sulfoxide; (v) being substantially insoluble in blood, and (vi) having a solubility in dimethyl sulfoxide of at least 10 mg/ml at 20° C. 
     
     
       3. The embolizing agent of  claim 2 , wherein an ester derivative of a polysaccharide in said water-soluble organic solvent has a concentration of at least one percent by weight. 
     
     
       4. The embolizing agent of  claim 2 , further comprising an appropriate contrast medium for use in angiography. 
     
     
       5. The embolizing agent of  claim 2 , wherein said arteriovenous aneurysm is a cerebral aneurysm. 
     
     
       6. A method of producing an embolizing agent, which comprises dissolving an embolizing material in dimethyl sulfoxide to give a solution having concentration of 1 to 10% by weight and viscosity of below 1,000 centipoises (cps) at 20° C., and collecting the resulting solution, said embolizing material comprising an ester derivative of a polysaccharide, wherein said polysaccharide is selected from the group consisting of pullulan and elsinan, said ester derivative having a weight-average molecular weight of 10,000 to 500,000 daltons, a ratio of the weight-average molecular weight to the number average molecular weight of below two, and an average substitution degree of acyl group of greater than 2.5; said ester derivative being substantially insoluble in blood, having a solubility in dimethyl sulfoxide of at least 10 mg/ml at 20° C.